In the global floor care industry, scrubber-drier floor cleaning machines apply water and surfactant to floors, loosen dirt and debris with brushes or pads, and remove the suspended soils and liquids to a dirty water tank with a vacuum system. The last part of the scrubber-drier that touches the floor is a squeegee. The squeegee determines how much water, dirt and surfactant is removed from the floor and how much is left behind.
A traditional squeegee assembly contains a front channeled squeegee and a rear un-channeled squeegee in close proximity. The squeegees have a generally rectangular shape and a lower, generally linear, edge for contacting a floor. The front and back squeegees are located in close proximity to create a vacuum chamber.
The rear squeegee is in contact with the floor and collects the dirty water and surfactant or soap solution in the vacuum chamber for pickup. The front squeegee contains slotted channels to control the entry of airflow and dirty water/surfactant into the vacuum chamber. Collected dirty water and surfactant are vacuumed to the dirty water tank for disposal.
The slotted channels of the front squeegee have a fixed size and configuration which is not adjustable. Thus, when a scrubber-drier floor cleaning machine traverses over an uneven floor surface (example: grouted tile), the squeegees will partially or wholly lose contact with the floor. This causes a loss of vacuum pressure due to the additional volume of air entering the vacuum chamber due to a seal break between the uneven floor surface and the generally linear surfaces of the squeegee lower edges. The result is that dirty water and surfactant are left behind on the floor.
Additionally, as the front squeegee wears, the overall water pick-up performance of the scrubber-drier machine will degrade until total failure of the squeegee, again due to a breakdown of the seal created between the squeegee and the floor. At this point, both the front and rear squeegees will typically need to be replaced.
The quality of floor cleaning is dependent on the ability of the squeegee assembly to allow dirty water and surfactant to enter the vacuum chamber of the scrubber-dryer and still maintain a sufficient seal with the floor so the vacuum system is not compromised. This is particularly true when cleaning uneven surfaces. Therefore, there have been a number of attempts to address the issue of maintaining a seal between the squeegee assembly and a floor while drawing dirty water and surfactant into the vacuum chamber of the scrubber-dryer machine.
U.S. Pat. No. 5,212,848 to Geyer discloses the addition of small spaced protuberances along the lower edge of the squeegee blade on the side of the squeegee assembly that leads when the scrubber-dryer moves backward. The protuberances permit water to enter the vacuum area of the scrubber-dryer when the machine moves backward by breaking the blade seal with the surface being cleaned.
U.S. Pat. No. 3,520,012 to Carabet et. al. discloses a squeegee blade with raised bumps along a front surface of the blade tip. In use, the lip bends backwards (when moving forward) and the bumps cause the lip to move up, permitting air and liquid to flow beneath the lip through the spaces between bumps.
U.S. Pat. No. 4,817,233 to Waldhauser discloses the use of corrugations or channels through the front blade and rear blade. On the front blade, the channels are open to permit liquid to flow through the blade when moving in a direction into the fluid, but an inner flap of the blade prevents fluid from moving through the blade when the cleaning machine is moved in an opposite direction, toward fluid accumulated behind the front blade.
U.S. Pat. No. 6,647,585 to Robinson discloses a floor-cleaning tool that includes a diverter capable of selectively directing a flow of a pressurized liquid from an inlet to either a first outlet or a second outlet. The tool utilizes parallel squeegee blades (44 a, b in the patent). In one embodiment, the blades appear to be corrugated on one side, smooth on the other, to allow fluid to pass between the troughs created on the corrugated side when the tool is moved in the direction of the corrugated side of the blades.
U.S. Pat. No. 5,918,346 to Suzuki discloses the use of a flexible blade having a serrated configuration, comprising a plurality of blade surfaces arranged adjacent to one another along a longitudinal dimension, the lower edges of the blade surfaces being slanted relative to a plane of the floor surface when not in contact with the floor surface.
U.S. Patent Publication No. US 2003/0028995 to Ikeda discloses the use of a flexible squeegee blade that engages the floor surface at an approximate 45 degree angle. When downward pressure is applied to the squeegee blade, a greater area of a lip of the squeegee blade is forced into contact with the floor surface to increase the wiping efficiency of the squeegee blade.
U.S. Pat. No. 9,038,237 to Wood discloses a squeegee assembly that includes front and rear flexible blades, each with a wiping edge. The rear blade includes at least one aperture extending there through in spaced relation from the wiping edge to improve air flow into the vacuum system.
U.S. Pat. No. 6,108,859 to Burgoon discloses a squeegee having a series of upwardly extending openings spaced along the lower edge of the squeegee. The openings are tapered as they extend upward from the lower edge of the squeegee. The wider gap in the openings, along the lower edge of the squeegee, permit liquid to pass through the squeegee. The narrower gap at the upper end of each opening limits passage of ambient air to help maintain a seal with the floor.
U.S. Pat. No. 5,933,911 to Windmeisser discloses the use of blades made of strips of adjacent ribbed rubber material.
U.S. Pat. No. 5,377,382 to Bores et. al. discloses the use of squeegee blades having slits for the passage of dirty water and soap.
U.S. Pat. No. 4,951,341 to Shears discloses the use of radially aligned bands of flaps positioned in side to side relation to one another on a support base. Slits are provided in the flaps.
U.S. Pat. No. 3,107,387 to S. Katt discloses an apertured blade tip.
U.S. Pat. No. 3,019,462 to Nash et. al. discloses a flexible blade tip in the shape of a diamond.
U.S. Pat. No. 1,849,663 to Finnell discloses a cleaning machine that utilizes a front blade with notches.
None of this prior art has resulted in a satisfactory squeegee assembly that has the ability to allow dirty water and surfactant to enter the vacuum chamber and still provide an adequate seal between the squeegee and the floor, particularly on an uneven surface.